Hawa Engineers Ltd. Manufactures Cast Iron Swing Check Type Reflux Valves. Hawa Engineers Ltd. Is an ISO 9001 certified company. Cast Iron Swing Check Type Reflux Valves are generally used to maintain flow of water in only one direction and stop the return flow of water which is self operative by pressure only. Cast Iron Swing Check Type Reflux Valves are used in water main lines all over the world especially in hilly areas. These can be fitted in vertical or horizontal position. These valves are ISI marked. The flanges of these valves are normally drilled as per 151:1538 but any type of drillings like BS: 10, DIN, ASA, etc. Can be provided. These valves can be supplied with door faces either of metal or rubber as per requirement.